Automated vehicle inspection system

ABSTRACT

The invention integrates a general purpose computer with a controller area network to effect an inspection regimen through the controller area network A convenient user interface, combining handheld instruments and convention displays and printers allows the driver to interact with the system. The computer provides storage for programs and processing power to implement test regimens in logical order relating to completion of the inspection.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates generally to commercial motorvehicles and more particularly to an automated vehicle inspection systemproviding the collection of selected data and prompting manualinspection and entry of other data to promote the generation ofelectronic inspection reports in an efficient and complete manner.

[0003] 2. Description of the Problem

[0004] Commercial transport regulations provide for periodic inspectionof, generation of inspection reports relating to, and documentation ofmaintenance on, commercial vehicles. Inspections include checkingnumerous operational aspects of the vehicle for conformity to normativeoperational standards, implementing a check off system for maintenancewhen indicated by inspection, as well as for scheduled maintenance, andvalidating the reports generated and keeping copies of the reports for aminimum time period.

[0005] Vehicle interactive on board computers (OBC) have been suggestedin the art for use in implementing inspection programs directed tomeeting regulations. The OBC suggested in U.S. Pat. No. 5,680,328 waspreferably a personal or lap top computer, which is used for receivingdata inputs from a driver or maintenance personnel as part of aninspection, and for providing for the collection of data from varioussensors placed on the vehicle. However, the '328 patent did not describea mechanism for actually collecting data from vehicle sensors. The OBCmay electronically store inspection reports, and provide copies of thesame on a display or in hard copy form.

[0006] Contemporary designs for the control and management of vehiclecomponents increasingly rely on methods derived from computernetworking. Digital data is exchanged between component controllers overa common physical layer such as a twisted shielded pair of wires.Intelligible communication between two or more device controllers amonga greater plurality of devices, all occurring over the common physicallayer, depends upon the communicating devices being able to discriminateamong messages they receive and to respond to those messages directed tothem. Such methods are well known in the art and are part of thestandards which the Society of Automotive Engineers (SAE) has publishedand continues to publish as part of the SAE J1939 protocol.

[0007] The J1939 protocol provides an open protocol and a definition ofthe performance requirements of the medium of the physical layer, butalso allows for development of proprietary protocols. The SAE J1939protocol is a specialized application of a controlled area network (CAN)and may be readily implemented utilizing commercial integrated circuitssuch as the C167 Integrated Circuit from Siemens of Germany.

[0008] The CAN protocol is an ISO standard (ISO 11898) for serial datacommunication, particularly aimed at automotive applications. The CANstandard includes a physical layer (including the data bus) and adata-link layer, which define useful message types, arbitration rulesfor bus access and methods for fault detection and fault confinement.The physical layer uses differential transmission on a twisted pair wirebus. A non-destructive bitwise arbitration is used to control access tothe bus. Messages are small, at most eight bytes, and are protected bychecksum error detection. There is no explicit address in the messages,instead, each message carries a numeric value which controls itspriority on the bus, and may also serve as an identification of thecontents of the message. CAN offers an error handling scheme thatresults in retransmitted messages when they are not properly received.CAN also provides means for removing faulty nodes from the bus. CANfurther adds the capability of supporting what are termed “higher layerprotocols” for standardizing startup procedures including bit ratesetting, distributing addresses among participating nodes or kinds ofmessages, determining the layout of the messages and routines for errorhandling on the system level.

[0009] Digital data communications over serial data paths are aneffective technique for reducing the number of dedicated communicationpaths between the numerous switches, sensors, devices and gaugesinstalled on the vehicles. Multiplexing the signals to and from localcontrollers and switches promises greater physical simplicity throughdisplacing much of the vehicle wiring harness, reducing manufacturingcosts, facilitating vehicle electrical load management, and enhancingsystem reliability.

[0010] It would be desirable to add intelligence to a vehicle controllerarea network conforming to the SAE J1939 standard to implementinspection regimens.

SUMMARY OF THE INVENTION

[0011] The invention integrates a general purpose computer with acontroller area network to effect an inspection regimen through thecontroller area network. A convenient user interface is based on acombination of one or more devices, including handheld instruments,conventional displays, keypads, pucks and printers, and allows thedriver to interact with the system. The computer provides storage forprograms and processing power to implement test regimens in a logicalorder relating to completion of the inspection. Full integration of anOBC to an individual vehicle inspection procedure to promote efficiencyand completeness, and to avoid possible damage to the vehicle, aidsorganization of the tasks called for by the inspection.

[0012] The substantially automated inspection system of the presentinvention works with a vehicle having an engine and with various vehiclesystems, characterized by measurable operating variables. The systemincludes an electrical system controller, a data communications busconnected at one node to the electrical system controller, a pluralityof sensors connected to the data communications bus for transmittingdata relating to the operating variables to the electrical systemcontroller, an user input/output interface, an on board computerconnected to the user input/output interface and to the datacommunications bus, the on board computer including memory, and avehicle inspection regimen stored in the memory and executable on the onboard computer. The program provides means for checking fluid levelsagainst one or more limits for various vehicle systems before enginestart, means for prompting an operator to start the engine if theoperating fluid levels meet applicable limits, and means for completingthe vehicle inspection regimen after an engine start.

[0013] Additional effects, features and advantages will be apparent inthe written description that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The novel features believed characteristic of the invention areset forth in the appended claims. The invention itself however, as wellas a preferred mode of use, further objects and advantages thereof, willbest be understood by reference to the following detailed description ofan illustrative embodiment when read in conjunction with theaccompanying drawings, wherein:

[0015]FIG. 1 is a partial cutaway view in perspective of a truckincorporating the invention;

[0016]FIG. 2 is a block diagram of a computer control, network andsensor system used to implement the inspection protocols; and

[0017]FIG. 3 is a flow chart illustrating the order of execution of theinspection program.

DETAILED DESCRIPTION OF THE INVENTION

[0018]FIG. 1 is a perspective view of a truck 11 and of an electricalcontrol system 10 installed on the vehicle. Electrical control system 10comprises a twisted pair (either shielded or unshielded) cable operatingas a serial data bus 18. One node of bus 18 is an electrical systemcontroller (ESC) 30, which is the central component of a vehicleelectronic control system. ESC 30 manages a number of vocationalcontrollers connected to bus 18 as nodes and positioned on truck 11.Collectively, bus 18 and the various nodes attached thereto form acontroller area network (CAN). Truck 11 includes conventional theconventional major systems of a vehicle, including an engine, a startersystem for the engine, brakes, a transmission and running lights.

[0019] Active vehicle components are typically controlled by one of agroup of autonomous, vocational controllers, which include a gaugecluster 14, an engine controller 20, a transmission controller 16, anauxiliary instrument and switch bank 12, and an antilock brake system(ABS) controller 22, all of which are nodes on serial data bus 18allowing two way communication with ESC 30. Autonomous controllersinclude local data processing and programming and are typically suppliedby the manufacturer of the controlled component. Bus 18 is a twistedpair cable constructed in accordance with SAE standard J1939. Althoughthe autonomous controllers handle many functions locally and canfunction independently of ESC 30, they report data to ESC 30 and canreceive operational requests from ESC 30.

[0020] An on board computer (OBC) 40 is also provided on truck cab 11.OBC 40 is based on a conventional personal or portable computerarchitecture and communicates with ESC 30, either over bus 18, ordirectly over a private bus. OBC 40 executes an inspection protocolleading to generation of required inspection and maintenance reports.

[0021]FIG. 2 is a block diagram of the electrical control system 10. ESC30 can collect data from a variety of sources, both over serial data bus18, or from sensors and devices directly connected the ESC. One sensoris illustrated as directly connected to a port on the ESC 30 is a rearaxle fluid level sensor 46. Electrical system controller 30 alsodirectly actuates lights 52 and can determine whether lights are workingfrom the amount of current drawn. ESC 30 and OBC 40 may communicate overthe serial data bus 18 or over a dedicated private bus 19. OBC 40includes conventional memory 43 (both volatile and non-volatile) andprogram execution capacities (CPU 41).

[0022] A serial data bus 18 conforming to the SAE J1939 standardprovides for data communication between ESC 30 and an engine controller20, a transmission controller 16, ABS controller 22, instrument andswitch bank 12, a gauge cluster 14 and one or more sensor interfacemodules. These controllers and modules are in turn connected to one ormore sensors which they collect data from and to which they may returndata which relate to the sensors to ESC 30. The specific connectionsbetween sensors and nodes of the system is exemplary, and otherarrangements than the one illustrated are possible.

[0023] Engine controller 20 is connected to an engine coolant levelsensor 25, an engine coolant temperature sensor 26, an engine oil levelsensor 27, an engine oil temperature sensor 28 and an engine oilpressure sensor 29. Engine coolant level sensor 25 is typically either apressure or capacitive type sensor, and is located at a position in thecoolant system allowing level sensing while the vehicle is stationary.The sensor has either a binary output (1=level acceptable, 0=addcoolant), or an analog output indicating percentage full (50% to 120%full). The sensor has a maximum sample rate of 1 measurement per second.Measurements can be broadcast on bus 18 formatted in accordance withJ1939 PGN65263. The engine coolant temperature sensor 26 is preferablylocated at a position in the engine coolant flow system allowing takingtemperature readings during engine operation. This sensor has a range of−40° C. to 125° C., with a maximum sampling rate of 1 reading persecond. Measurements can be taken after the engine has been running aminimum length of time. These measurements can be broadcast on bus 18formatted in accordance with J1939 PGN 65262.

[0024] Engine oil level sensor 27 is either a capacitive or pressuretype sensor, and is located at a position in the engine oil flow systemallowing engine oil level sensing while the vehicle is level. Sensor 27has either a binary output (1=level acceptable, 0=add oil), or an analogoutput indicating percentage full. If the output is analog, analog todigital conversion can be provided. Sensor 27 provides sampling at 2 Hz.Messages containing measurement data are transmitted over bus 18 inaccordance with J1939 PGN 65263. Engine oil temperature sensor 28 islocated in the oil flow system allowing measurements when the engine isrunning. Sensor 28 has a temperature operating range of −40° C. to 125°C., with a 1 Hz operating cycle. The message data format is J1939 PGN65262. Engine oil pressure sensor 29 is located in the oil flow systemto sample pressure during engine operation. Sensor 29 has an operatingrange of 0 psi to 200 psi with a sampling rate of 2 Hz. The messageformat is J1939 PGN 65263.

[0025] Transmission controller 16 is connected to a transmission fluidlevel sensor 32 and, usually, to a transmission fluid temperature sensor33. Transmission fluid level sensor 32 is typically a capacitive orpressure type sensor, and is located in the transmission fluid flowsystem to obtain fluid level measurements when the vehicle is level andstationary. Sensor 32 may have an analog output (50% to 120% of full) ora logical binary output (1=level acceptable, 0=add fluid). The samplingrate is 1 Hz. The signal is routed to the transmission controller 16 andbroadcast on bus 18 as a J1939 PGN 65272 signal. Transmission fluidsensor 33, while frequently connected to transmission controller 16, issometimes directly connected to ESC 30. The sensor has an operatingrange of 40° C. to 125° C. and a 1 Hz sampling rate. Measurements, ifrouted through transmission controller 16, are formatted for data bus 18as a J1939 PGN 65272.

[0026] The anti-lock brake system (ABS) controller 22 controls the brakesystem and is typically connected to brake system pressure sensors 34and brake actuation sensor 38, analysis of measurements from which allowdetermination of brake system functionality. OBC 40 will directexecution of an procedure to determine if the components of the vehiclebrake system are functioning correctly. Brake system pressures arebroadcast on bus 18 as a J1939 PGN 65274 signal. The OBC 40 can issueinstructions to ESC 30, some for further transmission to the appropriatecontroller, to set and hold engine speed, to depress or pump the brakes(via brake system actuation 37) and for setting and releasing theparking brake 51. Alternatively, OBC 40 may prompt the driver/operatorto carry out these tasks by the user I/O interface 36.

[0027] A power steering fluid level sensor 44 is located in a powersteering fluid reservoir (not shown) and may be connected either to ESC30, to engine controller 20, or, as illustrated here, to a sensorinterface module (SIM) 45, which communicates with ESC 30 over bus 18.The sensor has either a binary output (1=level acceptable, 0=add fluid),or an analog output indicating percentage full (from 50% to 120%). Thesensor sampling rate is 1 Hz. Transmission of the data is broadcast onbus 18 as a J1939 PGN 65272 message.

[0028] Fuel level sensors 48 are located in the vehicle's fuel tanks(not shown) and may be connected either to ESC 30, or, as illustratedhere, to a SIM 53, which communicates with ESC 30 over bus 18. Thesensor has an analog output indicating percentage full (from 0% to100%). The sensor sampling rate is 1 Hz. SIM 53 provides analog todigital conversion of the sensor output and broadcast of a data messageon bus 18 as a J1939 PGN 65276 message.

[0029] A windshield washer fluid level sensor 48 is located in awindshield washer fluid reservoir (not shown) and is typically connectedto a SIM 49, which communicates with ESC 30 over bus 18. The sensor hasa binary output (1=level acceptable, 0=add fluid). The sensor samplingrate is 1 Hz. Transmission of the data is broadcast on bus 18 as a J1939PGN 65276 message.

[0030] Electrical system controller (ESC) 30 is represented ascommunicating directly with a number of devices. Such connections may beprovided via ports which may be configured as power supply ports orserial data ports. Vehicle lights 52 are powered directly from ports onESC 30. The operational integrity of vehicle lights 52 may be determinedby current drawn. Other devices or sensors may similarly be directlyconnected to ESC 30, or they may be connected to bus 18 by a sensor ordevice interface module allowing data to be broadcast to ESC 30, ordevices and sensors may be handled by one of the other autonomouscontrollers, such as engine controller 20. Rear axle oil level sensor 46is connected either directly to ESC 30, or by a sensor interface moduleto bus 18. Sensor 46 may have either an analog output (50% to 120% offull), converted to digital data, or a binary output (1=levelacceptable, 0=add oil). The maximum sampling rate is 1 Hz. The J1939specification does not assign a message format for rear axledifferential oil level, requiring a proprietary message format iftransmission of data is handled by a SIM.

[0031] ESC 30 is connected to a battery condition sensor 24. Batterycondition sensor 24 preferably represents a system comprising ammeterscoupled to battery leads, battery voltage sensing and temperaturesensors. The determination of battery capacity and charge entailsexecution of an algorithm and reference to battery performance andhistory tables. The complexity of the system may vary from applicationto application and the system may, in some circumstances, be different.This algorithm may be executed by OBC 30, which also provides forstorage of a condition evaluation algorithm and the needed tables onmemory 43. OBC provides a CPU 41 to execute the algorithm. Data relatingto battery 23 is passed through ESC 30 from battery condition sensor 24.

[0032] ESC 30 is also connected to a tire pressure sensor 42. Tirepressure sensing may be provided for in a number of ways, includinginferential pressure measurement based on relative tire rotationalvelocities (in which case measurements may be handled by the ABScontroller 22), or by direct methods, such as battery powered sensorsmounted in the tires, in which case the pressure measurements may bedirectly communicated by a connection between the sensors 42 and ESC 30.A gauge cluster 14 and an instrument and switch bank 12 communicate withESC 30 over data bus 18. Additional components may be attached to bus 18and accommodated by the inspection routine if deemed important, such apump controller on a fuel tanker.

[0033] Driver inputs and prompts are handled by user I/O interface 36,which may be implemented in a touch screen display, conventionaldisplays, and keyboards or pads. I/O interface 36 is under the directcontrol of OBC 40, accepts driver indication of task completions,including in cab and walk around inspection items, and further directsaspects of the brake inspection routine which cannot be economicallyautomated. Driver acknowledgment of critical errors requiring immediateattention is provided. Prompts or buttons in interface 36 allow forthis. OBC 40 can provide for storage of reports in memory 43, whichincludes volatile and nonvolatile sections. Alternatively, the interface36 may include a printer allowing hard copies of the reports to beprinted. As described above, some aspects of the inspection procedurecan require driver actions, such as pumping or depressing the brakes,which are prompted on I/O interface 36. For walk around portions of theinspection a wireless handheld unit 136 may by be used by the driver toreceive prompts from OBC 40 via a wireless communication card 135.

[0034]FIG. 3 is a high level flow chart illustrating one possibleprocedure executed on OBC 30 to implement a preferred embodiment of theinvention. The exemplary procedure begins with movement of the vehiclekey to the on position from OFF (step 54). At step 56 it is determinedif the pre-trip inspection mode has been triggered. These can occur at:(1) the request of the driver; (2) each time the key is moved from offto on; (3) each key on instance after a minimum time interval since thelast key on instance; (4) each key on instance when the engine coolanttemperature is below a minimum threshold; (5) each occasion of a changeof driver; (6) a specific time of day; or (7) a minimum time intervalsince the last inspection. Particular triggering condition(s) areselected at the time when an OBC 30 is configured for a particularvehicle. The selections remain in effect until changed by theuser/operator. Interrogation of the inspection triggering conditions isindicated by step 55. If none of the conditions is matched the routineis exited.

[0035] The routine has a pre-engine start segment (steps through step76) and a post engine start segment (steps 78 to 97). If at step 56 aninspection is indicated, step 58 is executed to determine if the lastinspection report, stored in memory 43, has been signed off. By “signedoff” is usually taken as indication by a driver, possibly using apassword or code, that an inspection was performed. Step 58 can also beused to force branching to step 60, for example in the case that it issimply desired to review the report. If not, the branch to step 60 istaken and the driver is prompted to review the last inspection reportand to make notes and sign off on the report at step 62. Followingverification of signing off on the previous report (the YES branch fromstep 58 or following step 62), inquiry is made by the I/O interface 36to the driver as whether to begin the inspection (step 64). In not, forexample in the situation where review of a prior report had beenrequired, the program may be exited by step 65.

[0036] Following the YES branch from step 64 an inspection of thevehicle is begun. At step 66 all fluid level sensors are interrogated.Next, at step 68, the fluid level measurements are compared to minimacriteria for acceptability. For each fluid level not meeting recommendedlevels step 69 is executed along the NO branch from step 68 to set afluid level error flag. Upon analysis of all fluid levels processing isrepresented as progressing to a step 70 dealing with a default errorflag for automatic transmission fluid level. Low transmission fluidlevel can result in catastrophic transmission damage and an engine startis not permitted unless transmission fluid level is confirmed to beabove a minimum. If transmission fluid level is below the flag minimumanother fluid level error flag algorithm is run (step 74) followed bydetermination as to whether the fluid level, even though belowrecommended minimums, is sufficient to allow a safe start (step 76).These steps occur only if the message relating to transmission fluidlevel is expressed in terms of percentage of full. If it is not, theroutine is exited (step 77), otherwise, or following the YES branch fromstep 72, processing continues to step 78 and a prompt to the driver tostart the engine.

[0037] Once the engine has been started battery condition may beupdated. If battery condition is determined as unacceptable at step 80 aflag indicating the need for maintenance is set. Next the severalpressure and temperature readings are compared to norms, and if any areout of norm, processing is temporarily interrupted (step 82) to set theappropriate flag (step 83). Then step 84 is executed to compare tirepressure measurements against minimum required levels. If a tire hasinadequate pressure a flag is set (step 85). Following step 84 thedriver is prompted to turn on the vehicle's lights (step 86). At step 88the current drawn by the lights is compared with the minimum figureindicating that the lights are all working. If current draw is low aflag is set at step 89. Next the driver is prompted to perform in caband walk around checks. A handheld display device may be used at thispoint. Step 92 represents execution of brake system checks, which may beautomated or manual. Brake system is operation is compared withacceptable operating variables at step 94. If a variable is out of norma brake system error flag is set using a sub process (represented bystep 95). Finally, at step 96 a new inspection report is generated andthe program is exited (step 97).

[0038] The present invention automates many applicable portions of apre-trip inspection and provides immediate return information to thedriver in the form of a electronic inspection report. This in turn savesboth time and helps insure completeness of the reports.

[0039] While the invention is shown in only one of its forms, it is notthus limited but is susceptible to various changes and modificationswithout departing from the spirit and scope of the invention.

What is claimed is:
 1. Apparatus for implementing an inspection systemon a vehicle, comprising: a controller area network installed on thevehicle; a general purpose computer coupled for communication with thecontroller area network; a plurality of sensors broadcasting data overthe controller area network; means for routing the broadcast data to thegeneral purpose computer; programs stored on the general purposecomputer and executable on the general purpose computer to implementingan inspection protocol including the collection of data from the sensorsand directing activities of a driver moving through and around thevehicle; and a user interface for displaying results and instructions tothe driver.
 2. Apparatus as claimed in claim 1, the means for routingthe broadcast data further comprising an electrical system controller.3. Apparatus as claimed in claim 2, further comprising: at least a firstsensor connected to the electrical system controller; a pluralityautonomous controllers connected to the controller area network; and aplurality of additional sensors, each connected to one of the pluralityof autonomous controllers.
 4. Apparatus as claimed in claim 3, furthercomprising: the inspection protocol providing preset triggeringconditions for initiating inspection of the vehicle.
 5. Apparatus asclaimed in claim 4, the triggering conditions including, at the electionof a vehicle operator: (1) request by the driver; (2) movement of a keyfrom an off to an on position; (3) movement of the key from an off to anon position after a minimum time interval from the previous occurrence;(4) movement of the key from off to on when an engine coolanttemperature is below a minimum; (5) occasion of a change of driver ofthe vehicle; (6) a specific time day; and (7) a minimum time intervalsince the previous inspection.
 6. Apparatus as claimed in claim 4,further comprising two major portion of the inspection protocolincluding a first section before an vehicle engine is started and asecond section executed after the vehicle engine is running. 7.Apparatus as claimed in claim 6, wherein the inspection protocolincludes a preliminary section verifying that the previous inspectionwas validated.
 8. A vehicle, comprising: a vehicle controller areanetwork; a plurality of autonomous local controllers relating to majorvehicle systems connected to the vehicle controller area network; anelectrical system controller connected to the vehicle controller areanetwork for managing the plurality of autonomous local controllers; atleast one sensor interface module connected to the vehicle controllerarea network; a plurality of sensors, each connected to one of theplurality of autonomous local controllers, the electrical systemcontroller, or the vehicle controller area network; and a computercoupled for communication with the electrical system controller forimplementing inspection of vehicle operating conditions measured by theplurality of sensors through a program.
 9. The vehicle of claim 8,wherein the computer is a stored program general purpose computer andincludes stored programs specifying an inspection protocol and at leastone subsidiary program for implementing analysis of a vehicle system.10. The vehicle of claim 9, further comprising a user interface.
 11. Thevehicle of claim 10, wherein the stored programs further include meansfor evaluating a plurality of inspection triggering conditions.
 12. Thevehicle of claim 11, wherein the stored programs provide for inspectingthe vehicle in two stages, including a first stage before an engine isrunning and a second stage after the engine is running.
 13. A vehiclehaving an engine and various vehicle systems having operating fluids andcharacterized by operating fluid levels, the vehicle comprising: anelectronic system controller; a data communications bus connected at onenode to the electronic system controller; a plurality of sensorsconnected to the data communications bus for transmitting data to theelectronic system controller; an user input/output interface; an onboard computer connected to the user input/output interface and to thedata communications bus, the on board computer including memory; and avehicle inspection regimen stored in the memory and executable on the onboard computer, providing, means for checking fluid levels against oneor more limits for various vehicle systems before engine start, meansfor prompting an operator through the user input/output interface tostart the engine if the operating fluid levels meet applicable limits;and means for completing the vehicle inspection regimen after an enginestart.